Antenna



'K. POSTHUMUS ET AL 2,066,900

ANTENNA Jan. 5, 1937.

Original Fiied Sept. 21, 19s;

INVENTORS KLAAS POSTHUM us BALTHASAR VAN DER POL Patented Jan. 5,- 1937UNITED STATES PATENT OFFICE ANTENNA Klaas Posthumus and Balthasar vander Pol,

Eindhoven, Netherlands, assignors to Radio Corporation of America, acorporation of Delaware Claims.

This invention is a division of our United States Patent No. 2,031,065,granted February 18, 1936, based on an application filed in the UnitedStates September 19, 1929, and relates to antenna systems fortransmitting andreceiving wireless signals. More particularly, theinvention provides an arrangement in which a pure directional effect isobtained by means of an aerial system utilizing a plurality of aerialsor radiators.

According to the invention, the height of these aerials is substantiallyequal to or an odd multiple of the half Wave length of the oscillationsto be transmitted or received, and the said aerials are energized suchthat the operative direction is at right angles to the plane in whichthe aerials are located.

In the preferred embodiment, an arrangement is provided in which thespacing of the aerials is a half wave length and each aerial isconnected to one of two feeders present such that the energy in all theaerials is in phase. As an alternative, four feeders are provided andeach aerial is connected to two feeders such that the energy in all theaerials is in phase. An arrangement may be provided in which the spacingof the aerials is a half wave length and the aerials, which arealternately coupled in opposition, are connected to two central feeders.Alternatively, the spacing of the aerials may be an odd multiple of thehalf Wave length and a single feeder is connected to all the aerialssuch that the energy in all the aerials is in phase.

The invention will be more clearly understoodby reference to theaccompanying drawing, in which Figs. 1-7, inclusive, show some embodiments.

Fig. 1 shows an antenna having two feeders 2, 4 to which the aerials 6are connected. The aerials are spaced one wave length apart so that theyare in phase. This is necessary to secure a directional effect at rightangles to the plane of the aerials and this is so in the case with allthe aerial systems claimed.

Fig. 2 shows an antenna having likewise two feeders 2, 4.

In this case the aerials 8 are spaced a half wave length apart and asshown in the drawing are each only connected to one of the two feedersso as to ensure uniformity in phase.

The arrangement shown in Fig. 3, is identical with that of Fig. 2, butfor the width of the aerial system which is reduced by theinterconnection of coils ID in the feeders, such that the spacing of theradiators or aerials is still electrically a half wave length.

Fig. 4 shows an improvement in the arrangement of Fig. 3, the free endsof the aerials 8 shown in Fig. 3 being connected to two feeders M, 16 sothat the radiation of energy from the feeders, if any, is balanced bythe close proximity of a forward and a backward lead. The pairs offeeders l4, l4 and l6, l6 are preferably placed close together or theymay be separated by an even number of half Wave lengths to get properradiation addition in a direction perpendicular to their length.

Referring to Fig. 5, all the aerials are fed from one single feeder I8and so are they in Fig. 6, which shows the same antenna construction,but for the spacing of the aerials being very small so that in principleall the aerials are simultaneously in phase if their length is a halfwave length. That is to say, by bending adjacent half wave lengths, thecurrents therein, upon which radiation depends, are made to flow in thesame direction. As nevertheless the horizontal spacing is to be slightlytaken account of, the length of the aerials will practically be slightlysmaller.

Referring to Fig. 7, the aerials 20 are arranged on either side of twocentral feeders 22; in order to ensure uniformity in phase at a spacingof a half wave length, the aerials must be alternately coupled inopposition to the feeders.

What is claimed is:

1. A directive antenna system comprising a two wire transmission line,the wires of said line being parallel to each other, parallel radiatorsconnected to each of said wires and all located substantially in asingle plane, the radiators connected to one wire of said transmissionline being located substantially intermediate the radiators connected tothe other wire of said transmission line, said radiators being locatedbetween the wires of said transmission line.

2. A directive antenna system comprising a two Wire transmission line,the wires of said line being parallel to each other, parallel radiatorsconnected to each of said wires and all located substantially in asingle plane, the radiators connected to one wire of said transmissionline being located substantially intermediate the radiators connected tothe other wire of said transmission line, said radiators having a lengthsubstantially equal to one half the operating wave, the radiatorsconnected to the same wire of said line being efiectively electricallyseparated from one another along said wire by the length of theoperating wave, said radiators being located between the wires of saidtransmission line.

3. A directive antenna system comprising a two wire transmission line,the wires of said line being parallel to each other, parallel radiatorsconnected to each of said wires and all located substantially in asingle plane, the radiators connected to one wire of said transmissionline being located substantially intermediate the radiators connected tothe other wire of said transmission line, said radiators having a lengthsubstantially equal to one half the operating wave, the radiatorsconnected to the same wire of said line being efiectively electricallyseparated from one another along said wire by the length of theoperating wave, adjacent radiators being effectively electricallyseparated approximately by one-half the length of the operating wave,said radiators being located between the wires of said transmissionline.

4. A directive antenna system comprising a two wire transmission line,the wires of said line being parallel to each other, parallel radiatorsconnected to each of said wires and all located substantially in asingle plane, the radiators connected to one wire of said transmissionline being located substantially intermediate the radiators connected tothe other wire of said transmission line, said radiators having a lengthsubstantially equal to one half the operating wave, the radiatorsconnected to the same wire of said line being efiectively electricallyseparated from one another along said wire by the length of theoperating wave, and impedances serially connected in each wire ofsaidline between adjacent radiators for reducing the area of said antennasystem while still maintaining electrically the spacing between saidradiators.

5. A directive antenna system comprising a two wire transmission line,the wires of said line being parallel to each other and separated by adistance greater than one-half the length of the opcrating wave,parallel radiators connected to each of said wires and all locatedsubstantially in a single plane, the radiators connected to one wire ofsaid transmission line being located substantially intermediate theradiators connected to the other wire of said transmission line, saidradiators being located between the wires of said transmission line.

KLAAS POSTHUMUS. BALTHASAR VAN DER POL.

